Performance
· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.04 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.84 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
377 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.000
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
3.28 s
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
6.23 s
Page Load Progression
FPage Weight BudgetAction11.8 MB transferred, 130 requestsFIX
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Subset fonts to include only used characters, or switch to system font stacks.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DJS Execution CostAction2897ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.telegraaf.nl/_next/static/chunks/framework-136df7d2ca0cb23d.js | 620ms | 565ms | 7ms | 3rd |
| https://www.telegraaf.nl/ | 605ms | 43ms | 2ms | 3rd |
| https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/ui-web-nl-web.22ecd6bfac93de604efec0b75b2c796ee1675f92.js | 387ms | 330ms | 9ms | 3rd |
| Unattributable | 383ms | 68ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-TCTRVFNT>m_auth=luqLJVHzZCZ8FRNw0psBqA>m_preview=env-1>m_cookies_win=x | 110ms | 86ms | 16ms | 3rd |
| https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.22ecd6bfac93de604efec0b75b2c796ee1675f92.js | 107ms | 79ms | 11ms | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604160201/pubads_impl.js | 101ms | 58ms | 17ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-4S0SMBYPTG&cx=c>m=4e64k1h2 | 95ms | 79ms | 15ms | 3rd |
| https://cdn.kaching.eu.com/prebid/10.21.0/nl/prebid.js | 87ms | 48ms | 38ms | 3rd |
| https://www.telegraaf.nl/_next/static/chunks/pages/index-fa48c3b5e14ae0b0.js | 74ms | 74ms | 0ms | 3rd |
Showing top 10 of 15 scripts
FJS BundlesAction48 scripts, 1.3 MB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604160201/pubads_impl.js | 600 KB | 411 KB (69%) | ✓ | 3rd |
| https://www.telegraaf.nl/_next/static/chunks/pages/_app-9f68971ab19cc48d.js | 198 KB | 119 KB (60%) | ✓ | 3rd |
| https://prod-tmg.mhtr.be/public/tr/tracker.min.js | 157 KB | 112 KB (72%) | ✓ | 3rd |
| https://www.telegraaf.nl/_next/static/chunks/2248-e36bd15ff5938687.js | 180 KB | 111 KB (61%) | ✓ | 3rd |
| https://cdn.kaching.eu.com/prebid/10.21.0/nl/prebid.js | 138 KB | 101 KB (74%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-4S0SMBYPTG&cx=c>m=4e64k1h2 | 161 KB | 66 KB (41%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-TCTRVFNT>m_auth=luqLJVHzZCZ8FRNw0psBqA>m_preview=env-1>m_cookies_win=x | 173 KB | 66 KB (38%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-PLCMDRH4>m_auth=CxJv3UN7_Ke3WjOi3uYfVQ>m_preview=env-1>m_cookies_win=x | 142 KB | 54 KB (38%) | ✓ | 3rd |
| https://www.telegraaf.nl/_next/static/chunks/427ddc6b-10f35a46b3e2cd4b.js | 80 KB | 51 KB (67%) | ✓ | 3rd |
| https://sdk.privacy-center.org/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.22ecd6bfac93de604efec0b75b2c796ee1675f92.js | 103 KB | 44 KB (43%) | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
FPage Weight InventoryAction130 resources · 11.8 MB · 1.3 MB savings availableFIX
~1.3 MiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 130 resources | 11.8 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction41 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
A+Text CompressionAll text resources are compressedPASS
A+Font Loading6 fonts (540 KB)PASS
Web fonts
6
540 KB total
Render-blocking
0
of 6
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
Optimization checklist
- Preload critical fonts (priority=high)
- Use woff2 format for all fonts
- Set font-display to swap, optional, or fallback
- Subset large fonts (≤100 KB each)
Fixing the unchecked items could save ~247 KB and ~494 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall130 requests over 6840msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.telegraaf.nl www.telegraaf.nl | Other | 620ms | 65 KB | 44% | €7/mo | Costly |
www.telegraaf.nl www.telegraaf.nl | Other | 605ms | 103 KB | — | €7/mo | Costly |
sdk.privacy-center.org sdk.privacy-center.org | Other | 387ms | 55 KB | — | €4/mo | Costly |
Unattributable Unattributable | Other | 383ms | 0 KB | — | €4/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 110ms | 173 KB | 38% | €1/mo | Optional |
sdk.privacy-center.org sdk.privacy-center.org | Other | 107ms | 103 KB | 43% | €1/mo | Optional |
securepubads.g.doubleclick.net securepubads.g.doubleclick.net | Other | 101ms | 600 KB | 69% | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 95ms | 161 KB | 41% | €1/mo | Optional |
cdn.kaching.eu.com cdn.kaching.eu.com | Other | 87ms | 138 KB | 74% | €1/mo | Optional |
www.telegraaf.nl www.telegraaf.nl | Other | 74ms | 0 KB | — | €1/mo | Optional |
prod-tmg.mhtr.be prod-tmg.mhtr.be | Other | 70ms | 157 KB | 72% | €1/mo | Optional |
www.telegraaf.nl www.telegraaf.nl | Other | 68ms | 0 KB | — | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 65ms | 142 KB | 38% | €1/mo | Optional |
boot.pbstck.com boot.pbstck.com | Other | 64ms | 1 KB | — | €1/mo | Optional |
www.telegraaf.nl www.telegraaf.nl | Other | 58ms | 198 KB | 60% | €1/mo | Optional |
These scripts may cost more than they're worth
- www.telegraaf.nl adds 620ms and costs ~€7/month
- www.telegraaf.nl adds 605ms and costs ~€7/month
- sdk.privacy-center.org adds 387ms and costs ~€4/month
- Unattributable adds 383ms and costs ~€4/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾ ▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
www.telegraaf.nl takes 620ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.telegraaf.nl takes 605ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
sdk.privacy-center.org takes 387ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Unattributable takes 383ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
69% of securepubads.g.doubleclick.net's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
74% of cdn.kaching.eu.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
72% of prod-tmg.mhtr.be's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
60% of www.telegraaf.nl's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev